The usual sailboat that has two sails, is rigged with a mast with one sail extending aft of the mast and provided with a boom also extending aft of the mast, while the second sail, such as a jib, is located forward of the mast and may have an independent boom pivoted a distance from the mast and swingable through the fore triangle independently of the main boom. There have been rigs in which a single sail has extended in opposite directions from the mast such as in U.S. Pat. Nos. 2,147,501, 3,173,395 and British No. 847,310 or a single sail mounted on a tripod mast such as in U.S. Pat. No. 4,044,702 in which case booms have been used. Two independent sails mounted on the same mast with independent booms and gaffs are shown in the U.S. Pat. No. 685,943 but are not adapted to operate as a single boom means and allow the boat to go upwind. Also, single sails without booms that have extended forward and aft of a mast are shown in U.S. Pat. No. 4,054,100.
Conventional free sail rigs, such as are shown in the Schweitzer patent U.S. Pat. No. 3,487,800, are developed around the concept of a single mast with a rearwardly extending wishbone boom that serves the various purposes of tensioning the sail, providing the operator with a hand hold to balance himself, and supplying the means for controlling the sail and thereby the direction of the boat.